1. Field of the Invention
The present invention relates to a processing apparatus and a processing method for processing to dry substrates such as, for example, LCD substrates or semiconductor wafers.
2. Description of the Related Art
In fabrication of liquid crystal displays (LCD) or semiconductors, the technology called xe2x80x9clithographyxe2x80x9d is applied to form resist patterns on the surface of the LCD substrate or semiconductor wafer serving as the bases. Lithography processing contains various processes such as substrate cleaning, substrate drying, resist application to: the substrate surface and exposure and development of such resist. In these processes, heaters are used for the above drying process, for example. As an example of such heaters, a apparatus to place a substrate on a base for substrate heating is known. Such a heater is provided with several pins projecting upward from the base to support the bottom of the substrate when the substrate is received and passed so that it receives the substrate above the base by raising the pins and passes the received substrate to the base by lowering the pins. After heating on the base, it can lift the substrate above the base by pushing the substrate with pins from the bottom.
However, when a substrate made of an insulating material (LCD substrate, in particular) is placed on the base, static electricity tends to be generated between the substrate and the top of the base. For this reason, the substrate may adhere the top of the base and thereby preventing smooth lifting when it is to be lifted by pins from the base. In particular, an LCD substrate constituted by a thin glass plate is easily warped, which makes its separation from the base difficult In addition, when the substrate is lifted above the base, the polarization effect may cause charges of opposite polarities on the top and bottom face of the substrate.
It is an object of the present invention to provide a means for effectively removing charges on the top and bottom surface of the substrate lifted from the base.
To attain the above object, a processing apparatus according to the present invention comprising a base to place a substrate on it and pins to raise and lower the substrate on the base is provided with an ionizer beside the base.
An insulating substrate such as an LCD substrate is placed above the base so that the pins receive it at their top ends and go down to place it on the base. The substrate is subjected to heating or other processing on the base. After the processing, the substrate is lifted from the base by raising of the pins. While the substrate is being lifted, the ionizer positioned beside the substrate discharges ions to remove the charges on the top and bottom faces of the substrate.
Thus, the substrate is smoothly separated from the base and lifted by the pins.
In a method according to the present invention, the substrate is lifted from the base with the ion supply from a side of the substrate starting before the beginning of the operation to lift the substrate off the base and, the substrate is lifted at a first speed while at least a part of the substrate is in contact with the top of the base and at a second speed greater than the first speed above after the substrate has completely left the top of the base. Thus, the substrate can be smoothly lifted.